952 Oklahoma Almanac

Planet 9

Pluto may have been removed as the ninth planet of our but a bona-fide ninth planet may still exist. As of this writing, astronomers have found, and reinforced, circumstantial evidence of a large planet well past . The evidence consists of several KBO’s whose orbits appear to have been gravitationally affected by some object 10 – 20 times more massive than Earth. Something out there seems to be pulling on several KBO’s, altering and aligning their orbits. That may seem like weak evidence, but that’s exactly how Neptune was discovered. Calculations showed the gravity of some object appeared to affect Uranus’s orbit around the sun. Predictions of its likely location were made and a dedicated hunt produced the discovery of Neptune. The first evidence for Planet 9 came in 2014 when astronomers Chad Trujillo and Scott S. Sheppard inferred the possible existence of a massive trans-Neptunian planet from similarities in the orbits of the distant trans-Neptunian objects and 2012 VP 113. By itself, this study was merely interesting. But follow-up studies in 2016 by astronomers Konstantin Batygin and Michael E. Brown at Caltech explained how a massive outer planet would be the likeliest explanation for the similarities in orbits of six distant TNO objects. Together, the two studies carried some weight. Trujillo had been part of the team to find the first planet orbiting a distant star and Brown discovered the first large TNO that caused astronomers to reconsider the definition of “planet,” eventually leading to Pluto’s demotion. The astronomical community took note. No credible theories of planet formation can explain how such a large object can form that far from the sun. Astronomers have discovered numerous cases of gas giant planets, like Jupiter, orbiting closer to their parent star than Mercury does to our sun. Such planets can’t form that close to their star, either, so some process caused them to move inward from their original location. Obviously this isn’t always the case for such gas giant planets, as Jupiter and Saturn didn’t migrate inwards. Jupiter and Saturn’s gravity are both so large that astronomers believe the many, if not all, billions of objects in the formed closer in, near where Jupiter and Saturn now reside and the gravity of these two flung them to the outer reaches of the solar sys- tem, creating the Kuiper Belt. Other astronomers believe Planet 9, if it is real, originally formed around some other star, only to be torn away, becoming a free-floating Rogue Planet, before being captured by our sun’s gravity. Our sun, like most stars, formed in a cluster of rather tightly packed stars and that proximity can easily cause planets to be ripped from or exchanged with the other stars in the cluster. That explains why there are so many rogue planets and why an object 10-20 times the mass of Earth exists in a place where it shouldn’t be. Intense observational efforts underway seek to home in on the precise location of Planet 9. Before the two-year period of this book is up, we may again live in a nine-planet solar system. But either way, there likely will be continued cries to reinstate Pluto as a full- fledged planet. Conjunction

A conjunction occurs whenever two or more objects in our solar system appear close together in our sky. Many millions of miles separate the bodies in space, but from our viewpoint on Earth they seem to be very close. Two planets very rarely “line up,” appearing